The research project will (1) develop efficient, cost-effective methods for predicting the families who produce juvenile delinquents, and (2) explain why such youths become offenders. During the three-year period of the research project, prediction instruments will be selected, developed, and refined. A trial run of these instruments will be carried out on a sample of 30 youths known to be offenders and 30 youths not meeting the criteria for assignment to the at-risk group. In addition, a second sample of 210 boys, 70 10-year-olds, 70 13-year-olds, and 70 16-year-olds will be studied with these measures. The proposed prediction-methodology will be based upon a graded series of selection devices ranging from teachers' ratings to school records to home observation. Each source of information and each level of precision increases the true identification and reduces false identifications. The prediction methodology developed during the planning years will eventually be applied to a second, much larger sample during the main study period. The main study will follow at-risk and normal youths for nine years following original selection. On the basis of data gathered during the present and the eventual longitudinal projects a theory of the origins and development of delinquency will be developed.